1. Field of the Invention
This invention relates to a trolley for vegetables, fish, meat and so forth which is used at a supermarket, a restaurant or the like.
2. Description of the Prior Art
A trolley proposed by the inventor in Japanese Utility Model Publication No. 17945/1979 is composed of four support pipes (b) which are arranged at the four corners of a quadrilateral and which have casters (a) mounted on the lower ends thereof, a plurality of rack boards (c) having pipe cover portions (d) at four corners which are threaded over the support pipes (b), spacer pipes (e) threaded over the support pipes between the pipe cover portions (d) of vertically-adjacent rack boards (c), and caps (f) which are fitted over the upper ends of the support pipes (b). (See FIGS. 9 and 10.)
In the working area of a supermarket or a restaurant, such a trolley is frequently wheeled into and out of a refrigerator or a freezing store. In this case, there is a difference in temperature between the refrigerator or the cold store and the working area.
Therefore, in order to help prevent the operator of the trolley feeling cold and also to make the trolley lighter, the rack boards and the spacer pipes are formed of synthetic resin.
Since synthetic resin is weak, it is necessary to reinforce the rack boards and the spacer pipes by using a metal as the material of the support pipes.
However, since the coefficients of thermal expansion of metal and synthetic resin are strikingly different, differences arise in the degrees of expansion and contraction of the two materials when the trolley is wheeled into or out of the refrigerator or the cold store, so that a gap t is generated between each cap (f) and its pipe cover portion (d) of the uppermost rack board (c), making the trolley rickety. (FIG. 12)